1. Field of the Invention
The present invention relates to signs with surface relief, and in particular to signs encapsulated in a fired porcelainized enamel coating which is weather and vandal resistant.
2. Description of the Related Art
Substrates, signs and methods of producing the same are disclosed in the following patents:
______________________________________ U.S. Pat. No. Inventor(s) ______________________________________ 2,353,019 Dyer 2,581,310 Sweo 3,726,707 Prosser, et al. 3,961,112 Genevitz, et al. 4,074,010 Knight 4,075,049 Wood 4,084,032 Pasersky 4,225,908 Small, Jr. 5,084,309 Smith, et al. 5,091,224 Kushida, et al. 5,098,813 Nakano, et al. 5,162,160 Matsui, et al. 5,196,395 James, et al. 5,389,413 Condon, et al. 5,534,347 Chen, et al. ______________________________________
U.S. Pat. No. 2,353,019 to Dyer, discloses a method of etching steel, wherein steel sheets are dipped in ferric sulfate etching bath so that the sheet is prepared for a coating such as electroplating, enameling or other ornamental surfacing, such as tin or terne coatings.
U.S. Pat. No. 2,581,310 to Sweo, discloses a porcelain enamel article and method of producing same, wherein a surface of a steel work piece is cleaned and roughened to provide deep sharp edged pits therein, pickling in nitric acid after which a cover coat of porcelain enamel is applied to the roughened surface.
U.S. Pat. No. 3,726,707 to Prosser, et al., discloses porcelain enameling of steel, wherein nickel, cobalt and cooper are electrolessly deposited on steel after which enameling frit is coated to the steel.
U.S. Pat. No. 3,961,112 to Genevitz, et al., discloses luminous embossable tape which consists of a strippable two piece backing layer, a layer of adhesive adjacent thereto and a luminous layer which may be mixed and combined with the adhesive layer.
U.S. Pat. No. 4,074,010 to Knight, discloses ceramic-paint coatings wherein a material in finely divided form is applied as a first coat of ceramic paint, the coating is cured without fusing the ceramic paint, and then a second coat of ceramic paint is applied after which curing is done without paint. Curing is done at 750.degree. F. or lower and therefore, the paint is not a fused coating.
U.S. Pat. No. 4,075,049 to Wood, discloses a method of preparing retroreflective sheeting wherein a monolayer of glass spheres is disposed to provide pathways therebetween for flow of a resinous material in the pathways to link a film over the spheres with a film beneath the spheres to which the spheres are adhered and partially imbedded.
U.S. Pat. No. 4,084,032 to Pasersky, discloses a process for making hot stamping foil for producing textured surface effects consisting of a carrier sheet, a releasing lacquer coat applied to the carrier sheet, an opaque color coat applied to said releasing lacquer coat and a heat/pressure activatable resinous adhesive coat applied to said opaque color coat.
U.S. Pat. No. 4,225,908 to Small, Jr., discloses a lighting fixture and glass enclosure having high angle anti-reflective film, wherein the anti-reflective film is produced by a chemical etch/leach process which is porous and skeletonized, and has a high silica content.
U.S. Pat. No. 5,084,309 to Smith, et al. discloses a product presenting different artistic images in the presence and absence of ambient light and a fabrication method therefor, wherein a primary image is produced as a plurality of first image forming elements on a substrate, after which a substantially clear phosphorescent material overlays the primary image to create a secondary image as a plurality of second image forming elements. The primary image is visible in ambient light and the secondary image is visible in the absence of ambient light.
U.S. Pat. No. 5,091,224 to Kushida, et al. discloses a method of preparation of a surface-coated, metal-made ornamental article consisting of coating a metalica substrate with a glassy protecting coating to prevent blooming or whitening on the surface.
U.S. Pat. No. 5,098,813 to Nakano, et al., discloses a stimulable-phosphor radiation image storage panel using specified heat or heat and activator-containing gas treatment.
U.S. Pat. No. 5,162,160 to Matsui, et al., discloses a fluorescent screen consisting of a substrate formed of a fibrous light-scattering material and a filling mixture of an organic fluorescent substance, and a binder evenly disbursed within said fibrous light-scattering material.
U.S. Pat. No. 5,196,395 to James, et al., discloses a method for producing crystallographic boundary junctions in oxide superconducting thin films, wherein V-shaped grooves are etched on a face of a crystal substrate by anisotropic etchant.
U.S. Pat. No. 5,389,413 to Condon, et al., discloses three dimensional signage and a method of making same, consisting of a thermoplastic laminate, preferably transparent, with a sign face layer of thermo-plastics, a visual character adhered to the layer, a background color layer adhered to the layer, and a 3-D character in registration with an adhered to the background color layer.
U.S. Pat. No. 5,534,347 to Chen et al., discloses a fusing roll have a fluorocarbon-silicone barrier layer consisting of a cylindrical core coated with a layer of silicone elastomer upon which is coated a composition cured by heating the mixture for such to be cured.
Among the patents discussed above, there is no disclosure of signage consisting of a substrate having surface relief, such as relief lettering and/or Braille characters integrally formed from the substrate, and being encapsulated in fixed porcelain enamel another porcelain is selectively depositedto the relief lettering and/or Braille characters to provide a visual contrast between areas of relief and the underlying substrate, wherein the specifications of height, width, slope, spacing, and necessary ratios between such parameters comply with the Americans with Disabilities Act (of 1991 and 1992) as amended (hereinafter ADA).
It should be noted that among the visually impaired, approximately ten percent (10%) of such persons are able to read and understand Braille, while the remaining 90% rely on what is commonly referred to as "letter tracing". This is the impetus to produce signage with both relief lettering and Braille characters. Signage using this surface relief must comply with the ADA requirements which state in part " . . . letters and numbers shall have a width to height ratio between 3:5 and 1:1 and a stroke-to-height ratio between 1:5 and 1:10. Character height, as sized according to the viewing distance . . . 0.032" raised lettering not less than 5/8" height, no higher than 2"; and symbols in their own 6" high field and accompanied with Grade II Braille. Braille dot diameter 0.059", inter-dot spacing 0.090", horizontal separation between cells 0.241", vertical separation between cells 0.395". Characters and background of sign shall be an eggshell or matte (non-glare) finish. Characters shall meet a minimum 70% contrast to background."
The ADA specifically requires that with respect to signage, the alpha numerical text and symbols printed on the signs must be formed thereon to comply with certain size and viewing distance requirements. In particular, the text and characters must be in relief, i.e. projecting from the surface of the sign, in order to comply with the ADA. This construction and arrangement enables those with limited eyesight to discern or finger trace the sign and the messages conveyed, as well as enable the blind to read Braille characters of the sign.
It would therefore be advantageous to have a process of producing a sign with surface relief which complies with the ADA specifications and is protected from the weather, harmful chemicals and vandalism.
In addition, such a process should provide a sign which is easy to clean and maintain.